Plaid Cymru leader Ieuan Wyn Jones is to seek to shake off his party's constitutional fixation and re-focus on "bread and butter" politics.

Mr Jones will try to portray Plaid's defining policy of greater power for the Welsh Assembly as an essential tool to deliver better public services, rather than as an end in itself.

He will tell the party's spring conference on Saturday that Plaid must deliver a clearer message on the issues that people care about.

The party based its disappointing General Election campaign on the demand for the Assembly to be given the same powers as the Scottish Parliament.

But Mr Jones now concedes that campaign did not hit the mark with voters.

Speaking ahead of his keynote speech to the Swansea conference, he said: "There was a feeling that we did not focus sufficiently on the bread and butter issues such as health, education and the economy last year.

"People are primarily interested in those things. We want to say to people the constitutional arrangements underpin that. We do not want constitutional change for its own sake, but the Assembly needs more powers to deliver on health and the economy."

Plaid will use the conference to portray the party as a real alternative to a Labour administration at the Welsh Assembly.

Mr Jones says that means persuading voters he was serious about offering different policies to Labour, and convincing people he can deliver - in particular improvement to Wales's economy and NHS.

The Plaid leader will align himself with the "wreckers" of public service reforms, so maligned by Labour ministers at their spring conference in Cardiff last month.

Mr Jones will criticise Labour plans to increase the role of private companies in the public sector and underline Plaid's demands that public services were delivered by the public sector.

Plaid will also step up its courting of the trade unions, although Mr Jones is keen to avoid a "crass" appeal for them to abandon Labour for a new Welsh nationalist home.

"Things are changing rapidly," he said.

"We saw with the unrest over changes to the post office, the unions did not go to Welsh Labour, they came to us. We need to examine how we can build on that and create even better relations."

There will also be an appeal to the forgotten parts of Wales. The perception that the Assembly is concerned with South Wales at the expense of the rest was increased today with the announcement that Newport rather than Wrexham had won city status.

Whereas Labour has "tinkered" with addressing that issue, Plaid was determined to make fundamental changes, Mr Jones said.

He wants the Assembly to prove its commitment to the north and west by moving quango headquarters out of Cardiff to "show the government is serious about spreading prosperity".